Improvement in ore-roasting furnaces



Patented June 3, 1879.

INVENTO WITNESSES N. PETERS, PHOTOLITHOGRAPHER, WASHINGTON. D C.

UNITED STATES PATENT OFFICE.

DAVID W. BRUNTON, OF SILVER PEAK, NEVADA.

IMPROVEMENT IN ORE-ROASTING FURNACES.

Specification forming part of Letters Patent No. 216,148, dated J uno 3, 1879; application filed March 12, 1879.

fore constructed wherein the interior-dimen-.

sion lines were straight lines or regular curves from end to end. All roasting furnaces so constructed I have found in actual experience to be faulty in this, that the ore was roasted irregularly, owing to the variations of the heat in the products of combustion at various points of the length of the revolving roastingchamber. The result is, that at some parts of the furnace, where the body of ore was shallow, the ore exposed would become fused or burned, and in other parts of the furnace where the ore was of greater depth it would not be sufficiently roasted.

In this class of furnaces the heat from the products of combustion in the roasting-chamber is greatest at the center, and decreases toward the ends, the ratio of decrease being less from the center toward the end next the furnace than from the center toward the outer end of the roasting-chamber.

Having after a long experience discovered this fact, the object of my invention is to construct a furnace wherein this variation of heat in the roasting-chamber will be compensated for by the shape of the cylinder, and avoid the objections already cited.

My invention consists in a revolving roasting-furnace having an ore-containing roasting chamber or cylinder constructed with its interior longitudinal dimension in an irregular curve, so that the interior surface is farthest from the axial line of the cylinder near its center, nearest the axial line at a point near the exit of the products of combustion, and intermediately distant from the axial line near the entrance for the products of combustion,

whereby the body of ore in the cylinder is distributed throughout its length'in a depth directly proportionate to the amount of heat applied throughout its length.

In the said drawings, A A are two ends of the roasting-chamber, being slightly. concave, and having at their centers the openings a a for the draft from the fire-place to pass through. The body of the roasting-chamber is made with its interior surface, in its longitudinal dimension, in an irregular curve, as seen at b to b, Fig. 1. This configuration contracts the cylinder slightly from the end D to D.

When the ore is placed in the chamber, and the surface is on a line, L, just below the openings a a, a perpendicular dropped from the surface of the ore to the shell of the roastingchamberwould be longest about the center of the chamber, (see E,) shortest near the outer end, (see F,) and of intermediate length at the end next to the fire-place, (see Gr.)

Thus it will be seen that, starting from end A at a given curve, the size of the cylinder is increased toward the center in a direct ratio to the increase of heat, and from the center toward the outer end decreases in size'in a direct ratio to the decrease of heat, so that the ore is distributed directly in proportion to the heat applied by the furnace.

I am able in this furnace to thoroughly chloridize and bring the ground ore out of the roaster in an impalpable powder, whereas in all furnaces heretofore used the ore comes out in a burned red color, and containing from five to fifteen per cent. of the ore fused into lumps or balls, which have to be screened out andreturned to the crusher.

I am aware that ore-roasting furnaces have heretofore been made provided with revolving ore-containing chambers having their interior surfaces in curves of various descriptions; but none of them that I am aware of are constructed in an irregular curve of such peculiar gradation as to distribute the contained ore in a depth directly proportioned to the amount of the distribution of heat from the furnace.

Having thus described myinvention, what I claim as new, and desire to secure by Letters Patent, is

A revolving roasting-furnace provided with bustion, and intermediately distant from the an ore-containing cylinder or body having axial line near the entrance for the'produots its interior longitudinal surface in the irreguof combustion, substantially as set'forth. lar curve I) b-that'is to say, this surface be- DAVID W. BRUNTON.

ing farthest from the axial line of the oylin- Witnesses: der near the center, nearest the axial line at JOHN DE WITT WAgNER, -a point near the exit of the products of 00111- D. J. ToMPKINs. 

